StatefulSample.cs

//This uses Records to make the code smaller, even though it doesnt come out until C# 9
//IT also uses a new abstract class, that shouldnt count against it's line count: https://gist.github.com/Clancey/1df421c93ee20832d793a96b30fec997
public data class Model
	{
		public int Count { get; set; }
		public int Step { get; set; }
		public bool TimerOn { get; set; }
	}
	public enum Msg
	{
		Incrament,
		Decrament,
		Reset,
		SetStep,
		TimerToggled,
		TimedTick,
		TickTimer
	}
	public class StatefulMVUSample : StatefulView<Tuple<Msg, object>, Model>
	{
		public StatefulMVUSample() : base(new Model { Count = 0, Step = 1, TimerOn = false })
		{
		}
		public override Model Update(Tuple<Msg, object> message, Model model)
		{
			switch (message.Item1)
			{
				case Msg.Incrament:
					return model with { Count = model.Count + model.Step };
				case Msg.Decrament:
					return model with { Count = model.Count - model.Step };
				case Msg.Reset:
					return init();
				case Msg.SetStep:
					return model with { Step = (int)message.Item2 };
				case Msg.TimerToggled:
					var newModel = model with { TimerOn = (bool)message.Item2 };
					if (newModel.TimerOn)
						TickTimer();
					return newModel;
				case Msg.TimedTick:
					var newModel = model.TimerOn ? model with { Count = model.Count + model.Step } : model;
					if (newModel.TimerOn)
						TickTimer();
					return newModel;
				default:
					return model;
			}
		}

		public override View View(Model model) =>
			new VStack
			{
				new Text($"{model.Count}"),
				new Button("Increment",()=> Dispatch(new Tuple<Msg,object>(Msg.Incrament,null))),
				new Button("Decrement",()=> Dispatch(new Tuple<Msg,object>(Msg.Decrament,null))),
				new HStack
				{
					new Text("Timer"),
					new Toggle(model.TimerOn,(value)=> Dispatch(new Tuple<Msg,object>(Msg.TimerToggled,value)))
				},
				new Slider(model.Step,through:10,onEditingChanged: (value) => Dispatch(new Tuple<Msg, object>(Msg.SetStep,value))),
				new Text($"Step Size: {model.Step}"),
				new Button("Reset", ()=>  Dispatch(new Tuple<Msg, object>(Msg.Reset,null)))
			};
		Model init() => new Model { Count = 0, Step = 1, TimerOn = false };
		async void TickTimer() {
			await Task.Delay(200);
			Dispatch(new Tuple<Msg, object>(Msg.TimedTick,null));
		}
	}